The quarterly journal of the gemological institute of america
EDITORIAL
Studies on Tourmaline, Sapphire, Cultured Pearl, and a Reliquary of Legend…
Duncan Pay, Editor-in-Chief
An overview of the Spring 2019 Gems & Gemology content.
Articles (6)
A New Method for Determining Gem Tourmaline Species by LA-ICP-MS
Presents a simplified but comprehensive classification of gem tourmaline species based on quantitative measurement of six common major elements.
U-Pb Ages of Zircon Inclusions in Sapphires from Ratnapura and Balangoda (Sri Lanka) and Implications for Geographic Origin
Establishes a metamorphic origin for sapphire samples from these deposits, supported by their trace-element composition and inclusion characterization, including the age dating of zircon inclusions.
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The Talisman of Charlemagne: New Historical and Gemological Discoveries
Reveals new details about this historical jewel and the results of its first gemological analysis.
Provenance Discrimination of Freshwater Pearls by LA-ICP-MS and Linear Discriminant Analysis (LDA)
Investigates trace-element chemistry of freshwater natural pearls from North America and China with LA-ICP-MS and uses LDA to identify their origins.
Pleochroism and Color Change in Faceted Alexandrite: Influence of Cut and Sample Orientation
Shows how alexandrite’s color and color change are affected by cut and the orientation of table facets.
Land of Origins: A Gemological Expedition to Ethiopia
Documents a visit to the sapphire, opal, and emerald mining and trading areas of Ethiopia.
Regular Features
GEM NEWS INTERNATIONAL
Global coverage of gem sources, notable new gem materials, and recent industry developments.
DIAMONDS from the DEEP
Explores the role of diamonds in our understanding of the natural world.
THE DR. EDWARD J. GÜBELIN
MOST VALUABLE ARTICLE AWARD
The Color Origin of Gem Diaspore: Correlation to Corundum
Che Shen and Ren Lu
Gemological Characteristics of Sapphires from Yogo Gulch, Montana
Nathan D. Renfro, Aaron C. Palke, and Richard B. Berg
Natural-Color Green Diamonds: A Beautiful Conundrum
Christopher M. Breeding, Sally Eaton-Magaña, and James E. Shigley
